The ballots are burned in a stove after every second vote. The smoke from the stove comes out of a special chimney erected on top of the chapel in the days before the conclave starts. Black smoke means no decision has been made. White smoke signals that cardinals have chosen a new pope. The bells of Saint Peter’s Basilica will also ring, to help avoid possible confusion if the color of the smoke is gray. In times past, damp straw was added to the stove fire to create dark smoke, but since the 1960s chemicals have been used to create the effect.